单选题 As an operating system repeatedly allocates and frees storage space, many physically separated unused areas appear. This phenomenon is called ______.
A. fragmentation B. compaction C. swapping D. paging

【正确答案】 A
【答案解析】随着操作系统反复分配与释放存储空间，就会出现许多不连续的未用物理区域，这种现象称为碎片。